Hemorrhagic fever and encephalitis are both devastating clinical syndromes that can be caused by a large number of microbial agents. Some of the causative agents of these diseases have the potential to be weaponized or used as bioterrorist agents. Rapid diagnosis of the etiologic agent is critical to distinguish natural occurring cases from potential acts of bioterrorism. The goal of this project is to develop and validate an integrated diagnostic platform for detection of all viruses known to cause encephalitis and hemorrhagic fevers. The core of this technology combines a DNA microarray, containing a set of nucleic acid probes capable of hybridizing to essentially all known viruses, with a computational algorithm for calling the presence or absence of viruses in statistical fashion. In this application a DNA microarray capable of species-specific identification of all viruses associated with these diseases will be designed. The ability of this platform to detect multiple strains of each known virus using cultured viruses, spiked clinical samples and authentically infected clinical specimens will be explicitly validated. Furthermore, detection limits will be quantified and the ability of the platform to unambiguously characterize reassortant, recombinant and engineered viruses will be validated. Finally, the portability of the diagnostic assay will be evaluated by assessing the performance of the microarray diagnostic assay in a clinical setting. Development of improved diagnostic methods for viral detection, especially for potential bioterrorism agents, will dramatically increase public health preparedness. The goal of this project is to develop and validate a novel DNA microarray based diagnostic assay for viruses that cause hemorrhagic fever and encephalitis.